Have you double checked all your connections, All good & snug? Nothing shorting out anywhere in the case? Maybe a heat issue with its randomness. Check your temps & try stripping the case & point a fan at it. You seem to have added alot of new hardware, Maybe back stuff out one at a time.

I think it's all connected well....I replugged everything in, and the temps have been good. I'm beginning to wonder about the RAM...I know that memory conflicts can create these kinds of problems.

I thank you kboy, zero, alec, didi, and killians for your input. I won't be abble to work on the damn thing for the next week, am going out of town. But when I get back, I will figure this thing out and let you all know what the prob was.

Yeah maybe you can run Memtest on the Ram or just swap it with some extra if you or a buddy has some. Those damn ram test take forever & I still don't trust their results. Let us know when ya get back. We'll get ya going again.

I am still unaware of what causes this problem as it can be directed to so many different pieces of hardware, software and configurations, but I eventually resolved the problem.

To begin with, I have the same motherboard as you (A7N8X-X). The first thing I recommend to do is flash your bios. Goto the Asus website and get the latest software for your motherboard. Theres a program on the disc you recieved with the motherboard that can automatically find and install the latest software, therefore this will simplify the process.

If problems persist, go into bios and check your settings. See what your cpu is clocked at, and if it's overclocked to some extent, default it to it's original setting. This is to ensure there is no overheating taking place, that is causing your computer to reboot. It is unlikely though, because you will be informed of this if you have installed the software which came with the motherboard (asus probe). But then again, temperatures displayed on screen are not always correct.

The final thing I can recommend is formatting your computer. I formatted several times (I was using XP Professional at the time also), and although I recall problems persisting, this could have a positive effect.

I finally gave up solving the problem, and sent the Asus mobo back for a replacement. They would only replace it with the exact same brand and model. I just got the replacement back yesterday, so will be installing it in the next day or 2. I had the RAM checked at a local PC shop, and they said it checked out ok. I hope the new mobo will solve the problem. If not, I'll probably be back here looking for some more help.

I put the replacement mobo in tonight, and, so far, no problems! Apparently, the original mobo had a problem that was causing the repeated reboots, although I have no idea what that problem might have been. The computer has been on now for approximately 4 hours, and has been used for some graphics intensive applications, and has not rebooted or shut down.

Thank you all for your input....it's nice to know there is a place I can come for knowlegable help and advice.